That was described as hearsay by the Disclosures Tribunal chairman because it came from a disputed conversation between Sgt McCabe and the former chief of the Garda press office.

Judge Peter Charleton said: “I could not possibly rely on it at the present time, I appreciate that could change.”

Mr Callinan has strongly denied the claims and the judge has said there was no evidence of malpractice against him.

Martin Callinan has strongly denied the claims (Niall Carson/PA)

The sergeant faced unfounded and false allegations of sexual assault on a child and a Facebook post described him as “Maurice the Rat” after he made claims of wrongdoing among officers including the quashing of penalty points.

On Monday the tribunal was told former commissioner Mr Callinan ordered that Sgt McCabe be “buried” after the whistleblower made malpractice claims against officers near the Irish border and later escalated his complaints of bullying to the highest levels of the force.

During emotional testimony Sgt McCabe alleged ex-commissioner Callinan told Fianna Fail parliamentarian John McGuinness he had abused his own children and his nieces, and was not to be trusted.

Sgt McCabe said he was left feeling “isolated” and “alone” after a smear campaign allegedly ordered by Mr Callinan.

Separate and unrelated hearsay claims were also made surrounding another former Garda commissioner, Noirin O’Sullivan.

Garda documents before the Tribunal suggested she took Sgt McCabe’s complaints seriously.

Sgt McCabe relayed his recollection of a conversation with former Garda press chief Superintendent David Taylor.